It's best to piggyback on DNS rather than inventing on new scheme (address books, namecoin,..) since this would surely result in a petty holy war and would confuse users. But it would be a nice way to destroy ICAAN monopoly over the domains.
The .onion protocol should behave exactly as https for http, it's just a protocol upgrade. Instead of a green lock, you would get a purple lock indicating privacy.
To do the protocol upgrade, the SSL field annotation seems like the most robust way but I would go with `Alt-Svc` in the mean time since it's easier to implement (server and client side). To mitigate the privacy issue, tor could download a list of popular 'domain->.onion domain' (exactly like DNS caching)
The .onion protocol should behave exactly as https for http, it's just a protocol upgrade. Instead of a green lock, you would get a purple lock indicating privacy.
To do the protocol upgrade, the SSL field annotation seems like the most robust way but I would go with `Alt-Svc` in the mean time since it's easier to implement (server and client side). To mitigate the privacy issue, tor could download a list of popular 'domain->.onion domain' (exactly like DNS caching)